The word(s) "doubt" appears 83 time(s) in 77 verse(s) in Quran in Mohsin Khan translation.

(21) No doubt! Verily, the Auliya' of Allah [i.e. those who believe in the Oneness of Allah and fear Allah much (abstain from all kinds of sins and evil deeds which he has forbidden), and love Allah much (perform all kinds of good deeds which He has ordained)], no fear shall come upon them nor shall they grieve.

(22) No doubt! Verily, to Allah belongs whosoever is in the heavens and whosoever is in the earth. And those who worship and invoke others besides Allah, in fact they follow not (Allah's so-called) partners, they follow only a conjecture and they only invent lies.

(23) And recite to them the news of Nuh (Noah). When he said to his people: "O my people, if my stay (with you), and my reminding (you) of the Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.) of Allah is hard on you, then I put my trust in Allah. So devise your plot, you and your partners, and let not your plot be in doubt for you. Then pass your sentence on me and give me no respite.

(24) So if you (O Muhammad صلى الله عليه وسلم) are in doubt concerning that which We have revealed unto you, [i.e. that your name is written in the Taurat (Torah) and the Injeel (Gospel)], then ask those who are reading the Book [the Taurat (Torah) and the Injeel (Gospel)] before you. Verily, the truth has come to you from your Lord. So be not of those who doubt (it).

(25) Say (O Muhammad صلى الله عليه وسلم): "O you mankind! If you are in doubt as to my religion (Islam), then (know that) I will never worship those whom you worship besides Allah. But I worship Allah Who causes you to die, and I am commanded to be one of the believers.

(26) No doubt! They did fold up their breasts, that they may hide from Him. Surely, even when they cover themselves with their garments, He knows what they conceal and what they reveal. Verily, He is the All-Knower of the (innermost secrets) of the breasts.

(27) Can they (Muslims) who rely on a clear proof (the Qur'an) from their Lord, and whom a witness [Jibril (Gabriel عليه السلام)] from Him recites (follows) it (can they be equal with the disbelievers); and before it, came the Book of Musa (Moses), a guidance and a mercy, they believe therein, but those of the sects (Jews, Christians and all the other non-Muslim nations) that reject it (the Qur'an), the Fire will be their promised meeting-place. So be not in doubt about it (i.e. those who denied Prophet Muhammad صلى الله عليه و سلم and also denied all that which he brought from Allah. Surely, they will enter Hell). Verily, it is the truth from your Lord, but most of the mankind believe not.

(28) And who does more wrong than he who invents a lie against Allah. Such will be brought before their Lord, and the witnesses will say, "These are the ones who lied against their Lord!" No doubt! the curse of Allah is on the Zalimun (polytheists, wrong-doers, oppressors).

(29) And they were pursued by a curse in this world and (so they will be) on the Day of Resurrection. No doubt! Verily, 'Ad disbelieved in their Lord. So away with 'Ad, the people of Hud.

(30) They said: "O Salih! You have been among us as a figure of good hope (and we wished for you to be our chief) till this [new thing which you have brought that we leave our gods and worship your God (Allah) Alone]! Do you (now) forbid us the worship of what our fathers have worshipped? But we are really in grave doubt as to that to which you invite us (monotheism)."